diff options
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 75ccc0ee64f..c72a3f63d05 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -918,13 +918,14 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero, // TODO: This could be generalized to clearing any bit set in y where the // following bit is known to be unset in y. Value *Y = nullptr; - if (match(I->getOperand(0), m_Add(m_Specific(I->getOperand(1)), - m_Value(Y))) || - match(I->getOperand(1), m_Add(m_Specific(I->getOperand(0)), - m_Value(Y)))) { - APInt KnownZero3(BitWidth, 0), KnownOne3(BitWidth, 0); - computeKnownBits(Y, KnownZero3, KnownOne3, Depth + 1, Q); - if (KnownOne3.countTrailingOnes() > 0) + if (!KnownZero[0] && !KnownOne[0] && + (match(I->getOperand(0), m_Add(m_Specific(I->getOperand(1)), + m_Value(Y))) || + match(I->getOperand(1), m_Add(m_Specific(I->getOperand(0)), + m_Value(Y))))) { + KnownZero2.clearAllBits(); KnownOne2.clearAllBits(); + computeKnownBits(Y, KnownZero2, KnownOne2, Depth + 1, Q); + if (KnownOne2.countTrailingOnes() > 0) KnownZero.setBit(0); } break; |
